DE102021127811A1 - refrigerator and/or freezer - Google Patents

Abstract

The present invention relates to a refrigerator and/or freezer with a refrigerant circuit, the refrigerant circuit having a refrigerant line for conducting a refrigerant, a compressor for compressing the refrigerant, a condenser for condensing the refrigerant, an internal heat exchanger for heat exchange between a high-pressure side and a suction line of the compressor, and an expansion unit for expanding the refrigerant, an evaporator for evaporating the refrigerant, the expansion unit being or comprising a refrigerant permeable porous body. The invention is characterized in that the expansion unit is arranged downstream of the internal heat exchanger and upstream of the evaporator.

Description

The present invention relates to a refrigerator and/or freezer with a refrigerant circuit which includes a refrigerant line and in which a condenser and an evaporator located downstream of the condenser are arranged, with at least one expansion unit being arranged upstream of the evaporator, in which the refrigerant flows through is relaxed.

Conventional refrigerant circuits of known refrigerators and freezers include a condenser, an evaporator and an expansion unit in the form of a capillary arranged between the condenser and the evaporator. After flowing through the evaporator, the refrigerant reaches the compressor, where it is compressed and conveyed back to the condenser by the compressor.

During the operation of such refrigerators or freezers, the problem can arise that noises occur that are caused by the refrigerant flow in the refrigerant circuit. In order to counteract this, the channels in so-called rollbond or Z-bond evaporators are designed in such a way that the flow noise is as low as possible. This can be achieved by bypass channels, parallel channel structures, different or adapted pipe cross sections, etc. Furthermore, it is known to avoid noise in this area as much as possible by means of a suitable injection geometry, such as a trumpet-shaped design (injection trumpet) of the transition area between the capillary and the evaporator.

It is also known to design the outlet opening of the capillary in such a way that the outlet opening is as rounded as possible and without burrs.

In addition, there are also initial efforts in the prior art to form the expansion unit using a porous body that is permeable to a refrigerant. This promises a reduction in noise, but this cannot yet be achieved satisfactorily.

The present invention is based on the object of further developing a refrigerator or freezer of the type mentioned at the outset in such a way that the noise caused by the flow of the refrigerant is further reduced.

This object is achieved by a refrigerator and/or freezer having the features of claim 1. According to this, it is provided that the expansion unit, which comprises the porous body or is formed from it, is located in the refrigerant line between an internal heat exchanger and an evaporator.

According to the invention, it is therefore provided that a refrigerator and/or freezer according to the invention is provided with a refrigerant circuit, the refrigerant circuit comprising a refrigerant line for conducting a refrigerant, a compressor for compressing the refrigerant, a condenser for liquefying the refrigerant, an internal heat exchanger for heat exchange between a high pressure side and a suction line of the compressor, an expansion unit for expanding the refrigerant, and an evaporator for evaporating the refrigerant, the expansion unit being or comprising a liquid refrigerant permeable porous body. The invention is characterized in that the expansion unit is arranged downstream of the internal heat exchanger and upstream of the evaporator.

The person skilled in the art is aware that the refrigerant circuit runs from the compressor, typically a compressor, to the condenser, the high-pressure side of the internal heat exchanger of the expansion unit, the evaporator, the low-pressure side of the internal heat exchanger and back to the compressor.

Starting from the high-pressure side of the compressor, the high-pressure side of the coolant circuit typically extends at least as far as the evaporator, at the outlet of which the low-pressure side or the suction line of the compressor is then typically connected.

With regard to the arrangement position of the expansion unit, which is formed by a porous body permeable to liquid refrigerant, it has proven to be particularly advantageous if it is arranged downstream of the internal heat exchanger and upstream of the evaporator.

If the expansion unit is arranged on the high-pressure side of the refrigerant circuit in the area between the internal heat exchanger and the evaporator, the noise generated during the expansion of the refrigerant is particularly low.

According to a modification of the present invention, it can be provided that the porous body of the expansion unit brings about a fluid expansion and a noise-reducing flow homogenization at the same time. After this training, it is not the case that the porous medium or the porous body is only the noise-reducing Fluid homogenization is used and does not cause explicit fluid throttling, which is done for example by a non-porous body, but causes a fluid expansion and a noise-reducing flow homogenization.

Accordingly, it can be provided according to the present invention that the expansion unit is formed in one piece. It is therefore possible for the expansion unit to consist solely of a porous body which is introduced into the refrigerant circuit and through which the refrigerant has to flow.

Furthermore, it can be provided that the expansion unit is arranged in the outlet area of the internal heat exchanger, preferably directly at the outlet area of the internal heat exchanger.

According to the invention, it can also be provided that the expansion unit is arranged in a transition pipe section that completes a cross-sectional transition between the internal heat exchanger and an evaporator tube, with the transition pipe section preferably being shaped conically.

Furthermore, it can be provided according to the invention that the expansion unit is arranged in the inlet area of the evaporator, preferably directly at the inlet of the evaporator.

According to a further optional development of the invention, it can be provided that the expansion unit is arranged inside the evaporator, preferably in the flow channel of an evaporator roll-bond board, a tube-on-plate evaporator, a finned evaporator or a wound evaporator.

Alternatively and/or additionally, the invention can provide for the expansion unit to be pressed into a tube, with the porous body and the tube preferably having a cylindrical shape, the porous body having a cylindrical shape and the tube having a conical shape or the porous body as well as the tube have a conical shape. The tube can be part of the refrigerant line, so that all of the refrigerant flowing through the refrigerant circuit must flow through the porous body.

If the refrigerant pipe has a cylindrical shape just like the porous medium or the porous body itself, it is advantageous for a sealing press-in process if the porous body has a slight oversize. In order to facilitate the pressing-in process, it can also be advantageous if the porous body has an insertion or centering bevel in order to simplify pressing the porous body into the refrigerant pipe. For example, the porous body can be rounded off at one of its ends or provided with a chamfer on the edge area.

If the porous body has a cylindrical shape and the tube has a conical shape, the porous body centers itself due to the conical tube shape. The above configurations of the porous body and the refrigerant tube occur, for example, in the connecting tube between the internal heat exchanger outlet and the evaporator inlet on, in which the connecting tube slowly expands its cross-section.

If the porous body has a conical shape just like the refrigerant tube, this has the advantage over the configurations discussed above that a more uniform surface pressure occurs on the radial lateral surface of the porous body.

According to a further optional modification of the present invention, it can be provided that a tube is pressed onto the expansion unit, with the porous body and the tube preferably having a cylindrical shape. The porous body is arranged in a support sleeve, the length of which exceeds that of the porous body and, in the area of the excess length, is pressed against a wall of the pipe surrounding the support sleeve, or the porous body on one of its outer peripheral surfaces directly in the porous body itself or on one of the porous body-receiving sleeve has a thread which can be brought into connection with a corresponding counter-thread arranged on the inner circumference of the tube.

So if the coolant pipe is pressed onto the expansion unit and the porous body is cylindrical like the pipe, the porous expansion unit can be inserted into the pipe with sufficient play so that the pipe is pressed against the porous body from the outside and is positively connected to it .

According to an advantageous variant, it can be provided that when the porous body is inserted, an insertion limiter is provided in the coolant tube, for example a radial circumferential notch, a one-/two-sided groove or a one-/two-sided mandrel pressure, in order to specify the insertion depth.

Furthermore, it can be provided that the expansion unit is sintered in the form of the porous body in a thin-walled sleeve, wherein the Length of the sleeve is greater than that of the porous body. The area of the sleeve that is not covered by the porous body (sintering medium) can then be pressed from the inside out against the coolant pipe wall surrounding the sleeve. This has the advantage that the cross-sectional expansion of the coolant pipeline required between the internal heat exchanger and the evaporator can be carried out at the same time and a conical expansion of the pipe (injection trumpet) can be dispensed with.

If the porous body is provided with a thread on its radial lateral surface, it is conceivable on the one hand to sinter the porous body into a sleeve with an internal, rolled thread or on the other hand to sinter the thread itself. The counter-thread of the enclosing coolant tube could be pressed into the soft material of the coolant tube (e.g. aluminum or copper material), similar to an aluminum screw cap on a glass bottle.

According to an advantageous development of the present invention, it can be provided that a notch (slot or Phillips) is provided on one or both end faces of the porous body in order to be able to screw the porous body into the tube. The notch can be introduced, for example, by means of the appropriate shaping during sintering.

According to the present invention, it can therefore be provided that the porous body has an essentially cylindrical shape, has a thread on its outer peripheral surface and/or has a notch on one of its two end faces for screwing in the porous body.

In general, when connecting the porous body and the coolant pipe, care must be taken to ensure that the coolant fluid flows through the porous medium and not within a remaining gap between the porous body and the pipe wall enclosing the body. In such a case of a leakage mass flow past the porous body or the expansion unit, the defined refrigerant expansion would no longer be guaranteed.

At this point it is pointed out that the terms "a" and "an" do not necessarily refer to exactly one of the elements, although this represents a possible embodiment, but can also refer to a plurality of elements. Likewise, the use of the plural also includes the presence of the element in question in the singular and conversely the singular also includes several of the elements in question.

• 1a: eine schematische Darstellung eines herkömmlichen Kältem ittelkreislaufs,
• 1 b: eine schematische Darstellung eines erfindungsgemäßen Kältem ittelkreislaufs,
• 2a-c: unterschiedliche schematische Darstellungen, bei dem der poröse Körper in ein zylindrisches Kältemittelrohr eingepresst wird,
• 3a-b: unterschiedliche schematische Darstellungen, bei dem das Kältemittelrohr auf den porösen Körper aufgepresst wird, und
• 4: eine schematische Darstellung, bei dem der poröse Körper mit einem Gewinde in ein mit einem Gegengewinde versehenes Kältemittelrohr eingeschraubt wird.

Further features, details and advantages of the invention can be seen from the following description of the figures. show:

• 1a : a schematic representation of a conventional refrigerant circuit,
• 1 b : a schematic representation of a refrigerant circuit according to the invention,
• 2a-c : different schematic representations, in which the porous body is pressed into a cylindrical refrigerant tube,
• 3a-b : different schematic representations in which the refrigerant tube is pressed onto the porous body, and
• 4 1: a schematic representation in which the porous body is screwed with a thread into a refrigerant pipe provided with a counter-thread.

1a shows a conventional refrigerant circuit 1, in which a refrigerant line 2 connects a compressor 3, a condenser 4 and an evaporator 7. The evaporator 7 then leads the refrigerant to the suction side of the compressor 3. An expansion unit 6 (in the present case a capillary) is also provided between the condenser 4 and the evaporator 7. In addition, there is an internal heat exchanger 5 in which a part of the refrigerant line 2 (ie the suction line) downstream from the evaporator 7 is in a heat-exchanging connection with the high-pressure side.

The advantages of such an internal heat transfer lie in the improved cooling capacity of the evaporator that can be achieved as a result.

1b shows a refrigerant circuit 1 according to the invention, in which a refrigerant line 2 connects a compressor 3, a condenser 4 and an evaporator 7. The evaporator 7 then leads the refrigerant to the suction side of the compressor 3. There is also an internal heat exchanger 5, in which a part of the refrigerant line 2 (i.e. the suction line) downstream from the evaporator 7 is in a heat-exchanging connection with the high-pressure side.

The arrangement of the expansion unit 6, which according to the invention is formed by a porous body or includes this, is provided between the condenser 4 and the evaporator 7 downstream of the internal heat exchanger 5.

As a result, particularly low noise levels can be achieved when the refrigerant expands.

2a until 2c show different ways how the porous body 8 (also called: porous medium) can be pressed into a cylindrically shaped coolant line pipe 9.

2a FIG. 12 shows a configuration in which the porous medium 8 is formed in a cylindrical shape just like the coolant pipe 9. FIG. In a first step, which 2A characterized by a number 1 shown in a circle, the porous medium 8 is pressed into the coolant pipe 9 with a certain force. The porous medium 8 is slightly oversized, so that there is a clamping effect between the porous medium 8 and the coolant line pipe 9 when it is pressed in. In order to simplify the pressing of the porous medium 8 into the coolant line pipe 9 , the porous medium 8 can have an insertion/centering bevel, which can be implemented, for example, by a chamfer, a rounding or the like on the end face of the porous medium 8 .

In the lower part of 2a you can then see the porous medium 8 pressed into the coolant line pipe 9. To the left of this you can see different configurations of the insertion/centring bevel on the porous medium 8.

2 B shows a configuration in which the porous medium 8 has a cylindrical shape and the coolant line pipe 9 has a conical shape. For example, the porous medium 8 can be pressed into the cross-sectionally expanding connecting tube between the inner heat exchanger outlet and the evaporator inlet. Due to the conical shape of the tube, the porous medium 8 centers itself so that compared to the in 2a described design a centering bevel is not required. As in 2 B shown, the coolant line tube 9 can be formed from a flexible material that adapts to the outer contour of the porous medium 8 .

2c describes the case in which both the porous medium 8 and the coolant pipe 9 have a conical shape. This has compared to the in 2 B described case the advantage that on the lateral surface of the porous medium 8 acts a more uniform surface pressure.

3a and 3b show the case in which the coolant pipe 9 is pressed onto the porous medium 8. The diameter of the coolant line pipe 9 is reduced by the pressing and clamps the inserted porous medium firmly.

3a shows the pressing of the coolant line pipe 9 onto the porous medium 8. In this case, the porous medium 9 is introduced into the coolant line pipe 9 in a first step. The diameter of the coolant line pipe 9 is dimensioned in such a way that there is sufficient play between the outer circumference of the porous medium 8 and the inner circumference of the coolant line pipe 9 . In order to now fix the porous medium 8 in the coolant line pipe 9 , a radially inwardly directed force is exerted on the outside of the coolant line pipe 9 , which leads to a deformation of the coolant line pipe 9 . As a result, the porous medium 8 is positively connected to the coolant line pipe 9 . When the porous medium 8 is inserted, the insertion depth can be defined by an insertion limiter (for example a radial, circumferential notch, a one- or two-sided groove or a one- or two-sided indented pressure). The insertion limiter prevents the porous medium 8 from slipping through when it is inserted into the coolant line pipe 9. This ensures that the porous medium 8 is arranged at a predetermined point, so that the compression of the coolant line pipe 9 causes the desired fastening effect with the porous medium 8.

A metal in particular comes into consideration as the preferred material for the coolant line pipe 9 . A sintered metal material, for example, can be used as the porous medium 8 .

3b shows a further embodiment of how the porous medium 8 is pressed into the coolant line pipe 9 . The porous medium is first sintered into a sleeve 10, the length of which is greater than that of the porous medium 8. The protruding area of the sleeve can be pressed from the inside outwards against the enclosing pipe wall 9 after it has been placed in the coolant line pipe 9. This has the advantage that the cross-section expansion of the pipeline required at the system point between the internal heat exchanger and the evaporator can be carried out at the same time and the conical expansion of the pipe (injection trumpet) can be dispensed with.

4 shows a further embodiment of the present invention, in which the porous medium 8 is screwed into the coolant line pipe 9 .

It is provided that the porous medium 8 is provided with a thread 11 on its radial lateral surface. It is thus conceivable on the one hand to sinter the porous medium 8 in a sleeve with an internal rolled thread or on the other hand to sinter the thread itself. The mating thread 12 of the enclosing coolant line pipe 9 can, similar to the aluminum screw cap of a glass bottle, be screwed into the pipe itself, which is made of a soft aluminum or Kup fermaterial can be pressed. In order to be able to screw the porous medium 8 into the coolant line pipe 9, a notch 13 (e.g. slot or cross slot) can advantageously be provided on one or both end faces, which is introduced by means of the corresponding shaping during sintering.

What all the different embodiments have in common is that care must be taken to ensure that no fluid can flow past the porous medium 8 but must all flow through the porous medium 8 . If this is not the case, a leakage flow occurs which ensures that the defined refrigerant expansion of the porous component is no longer guaranteed.

Claims (10)

Refrigerator and/or freezer with a refrigerant circuit, the refrigerant circuit comprising: a refrigerant line for conducting a refrigerant, a compressor for compressing the refrigerant, a condenser for condensing the refrigerant, an internal heat exchanger for heat exchange between a high-pressure side and a suction line of the compressor, an expansion unit for expanding the refrigerant, and an evaporator for evaporating the refrigerant, the expansion unit being or comprising a porous body permeable to refrigerant, characterized in that the expansion unit is arranged downstream of the internal heat exchanger and upstream of the evaporator. Refrigerator and/or freezer according to the preceding claim 1 , wherein the porous body of the expansion unit causes a fluid expansion and a noise-reducing flow homogenization at the same time. The refrigerator and/or freezer according to any one of the preceding claims, wherein the expansion unit is molded in one piece. The refrigerator and/or freezer according to one of the preceding claims, wherein the expansion unit is arranged in the outlet area of the internal heat exchanger, preferably directly at the outlet area of the internal heat exchanger. Refrigerator and/or freezer according to one of the preceding Claims 1 - 3 , wherein the expansion unit is arranged in a transition pipe section, which completes a cross-sectional transition between the internal heat exchanger and an evaporator tube, the transition pipe section preferably being shaped conically. Refrigerator and/or freezer according to one of the preceding Claims 1 - 3 , wherein the expansion unit is arranged in the inlet area of the evaporator, preferably directly at the inlet of the evaporator. Refrigerator and/or freezer according to one of the preceding Claims 1 - 3 , wherein the expansion unit is arranged within the evaporator, preferably in the flow channel of an evaporator roll-bond board, a tube-on-plate evaporator, a finned evaporator or a wound evaporator. Cooling and / or freezer according to one of the preceding claims, wherein the expansion unit is pressed into a tube, wherein preferably the porous body and the tube have a cylindrical shape, the porous body has a cylindrical shape and the tube has a conical shape or the porous body as well as the tube have a conical shape. Cooling and/or freezing device according to one of the preceding claims, wherein a tube is pressed onto the expansion unit, the porous body and the tube preferably having a cylindrical shape, the porous body being arranged in a support sleeve whose length is that of the porous body and is pressed in the region of the excess length against a wall of the pipe surrounding the support sleeve, or the porous body has a thread on one of its outer peripheral surfaces directly in the porous body itself or on a sleeve accommodating the porous body, which thread has a corresponding thread on the inner circumference of the pipe arranged mating thread can be brought into connection. The refrigerator and/or freezer according to any one of the preceding claims, wherein the porous body has a substantially cylindrical shape, is threaded on its outer peripheral surface, and has a notch on one of its two end faces for screwing in the porous body.

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